MIXED-LIGAND LANTHANIDE COMPLEXES .7. COMPLEXES OF 1,10-PHENANTHROLINE AND THIOCYANATE

The thiocyanatoaqua-tris(1,10-phenanthroline) lanthanide(III)thiocyanates, [Ln(phen)(3)(H2O)(SCN)](SCN)(2) (where Ln = La-III and all trivalent lanthanides, except Pm and Lu) have been synthesized and characterized. The molar conductances, IR spectra and thermograms show the presence of both coordinated and non-coordinated thiocyanate. The complexes are eight-coordinate. Very large chemical shifts are observed in the NMR spectra of paramagnetic complexes. The interelectronic and covalency parameters calculated for the complexes show the covalent nature of bonding between the metal and the ligand. The oscillator strengths of the f-f transitions are calculated and discussed. The complexes appear to accept one solvent molecule (DMSO) and become nine-coordinate in solution.